Is there any significant difference between 2.67 and 2.73 in terms of 3D printing?
If you are just starting with blender, the DVD in question should give you a good idea of how things work, and you should be OK using current versions.

While some things have indeed changed since version 2.67, the main structure of the blender's User Interface has not. Blender has been very good in terms of keeping backwards compatibility, except for versions previous to 2.5, where a major overhaul did take place. But even that overhaul was to the UI, and files created in older versions open and can be edited in current versions. Note though, that if you're using a current version of Blender, you'll want to use the box in the lower left of the files dialog screen that allows one to open the file without changing the UI; otherwise, when you open a file, one sees the UI with which the file was created. 

If there are things that are dramatically different on newer versions, like plugins that are not up to date, or you just can't find the tool in today's version, don't worry, you can still download older versions of blender here: http://download.blender.org/release/ .

Once you get a general idea of how blender works you'll find that newer versions are quite a bit better, with less bugs and much easier to use than previous ones. And if you get stuck... you can always ask questions here or in other forums. Happy blending.